Core drill construction



1933- J. c. S-METHERMAN 2,141,800

CORE DRILL CONSTRUCTION Filed Nov. 27, 1957 2 Sheets-Sheet 2 1 36. E 4. I/11111111 fi/a/ 5g 6:- I 62 H oz III/III,

Patented Dec. 21, 1938 UNITED STATES.

CORE DRILL CONSTRUCTION Jesse C. Smetherman, Bakersfield, Calif., assignor to Globe Oil Tools Company, Los Nietos, Calif., a corporation of California Application November 27, 1937, Serial No. 176,859

8 Claims. (Cl. 255-72) This invention relates to well drilling tools and .relates more particularly to a core drill of the wire line type. A general object of this invention is to provide a core drill of the character I; mentioned that is practical and effective in operation and that is simple and inexpensive to manufacture and service.

Another object of this invention is to provide a wire line core drill embodying novel and very ef- 10 fective means for allowing the inner barrel to retract when hard earth formations are encountered.

Another object of this invention is to provide a core drill of the character mentioned embody- 16 ing an improved and simplified latch means for retaining the inner barrel in core receiving position in the outer barrel.

Another object of this invention is to provide a core drill of the character mentioned embody- 20 ing dependable means on the outer barrel for latching the inner barrel in place, the latch means being releasable by a spear type grapple employed to withdraw the inner barrel from the drill when a core has been taken.

25 A further object of this invention is to provide a core drill of the character mentioned in which the inner barrel is provided with means engageable by a spear lowered into the drilling string on a line or cable for the purpose of removing the 30 inner barrel after the same has received a core.

The various objects and features of my invention will be fully understood from the following detailed description of a typical preferred form 1 and application of the invention, throughout 35 which description reference is made to the accompanying drawings, in which:

Fig. 1 is a longitudinal detailed sectional view of the core drill provided by this invention illustrating the inner barrel in the operative position.

40 Fig. 2 is an enlarged fragmentary vertical detailedsectional view illustrating the latch means and the adjacent parts with the latch means in the normal condition. Fig. 3 is a view similar to Fig. 2 showing a spear holding the latch means 45 released and in lifting engagement with the inner barrel. Figs. 4 and 5 are fragmentary-vertical detailed sectional views of the lower portion of the spear with thehooks in their normal positions. Fig. 6 is an enlarged fragmentary vertical 50 detailed sectional view of the core catcher and Fig. 7 is a fragmentary horizontal detailed sec tional view taken as indicated by line on Fig. 2.

The improved core drill of the present inven- 55 tion includes, generally, an outer barrel l carrying a cuttinghead ll, an inner barrel l2 in sertable in and removable from the outer barrel I 0 and latch means 13 for removably retaining the inner-barrel l2 in position to receive a core.

The outer barrel [0 is adapted to be connected with the lower end of a rotary well drilling string S. The barrel I0 is an elongate tubular assembly carrying the cutting head II and adapted to receive the core receiving barrel l2. In the preferred construction illustrated the outer barrel includes a top sub M provided at its upper end with a threaded pin l5 for connecting with the drilling string S. The longitudinal opening [6 of the top sub l4 constitutes the continuation of the lower end of the opening in the drilling string 15 S. In accordance with the invention an annular downwardly facing shoulder I! is provided in the sub I4. The shoulder 11 may be provided on the wall of the opening I6 some distance above the lower end of the sub. The outer barrel l0 further includes an intermediate sub I8 threaded to the lower end of the sub l4 and a main barrel section l9 threaded to the-lower end of the sub I8.

The cutting head H may be threaded on the lower end of a sub 2| which in turn may be threaded to the lower end of the main barrel section IS. The head II is a tubular or annular member having a central vertical opening 22. Suitable cutting means are provided on the head l I. In the particular case illustrated in the drawings the cutting head I I is provided with downwardly and outwardly projecting'blades 23 for acting on the earth formation. The blades 23 have parts 24 for trimming the core for reception in the inner barrel l2. The blades 23 are 35. operable to make an annular cut in the earth formation and to leave a' core. for reception by the inner barrel 1 2. The circulation fluid usually employed in the rotary method of well drilling is adapted to pass downwardly through the outer 40 barrel l0 and ports 25 are provided in the head II for the discharge of the circulation fluid.

The inner barrel I2 is a tubular member or structure adapted to be dropped or lowered through the drilling string S into the outer barrel ID to receive and retain a core of the earth formation and is adapted to be withdrawn on a line or cable to carry the core to the ground surface. The inner barrel l2 includes a tubular main section 26 adapted to extend longitudinally through the section l9 and the sub 2| when the inner barrel is, in position in the drill. A suitable core catcher is provided on the lower end of the inner barrel l2 to grip and retain the core. The core catcher may include a tubular shell 21 threaded on the lower end of the section 23. The

shell 21 is provided with an internal flange 33 adjacent its lower end and a floating ring 2! is arranged in the shell 21 between the flange and the lower end of the section 28. Upwardly and inwardly projecting spring fingers are attached to the inner side of the ring 23 to cooperate with the core. In practice there will be vertically spaced rows of spring fingers 33 as illustrated in Fig. 6. The fingers are adapted to permit the free entrance or e of the core into the inner barrel 12 during the coring operation and are operable to grip and supp rt erably of substantially the same external diameter as the'section 28. The member 3| and the section 26 extend through the sub l3 with suitable clearance and the section 23 extends through the outer barrel section I! with substantial clearance, leaving, a continuous annular fluid-passage P'for conducting the circulation fluid downwardly to the ports 25 in the head H. The member 3| has a central longitudinal opening 32 communicating with the upper end of the barrel section 26. The lower portion of the opening-32 is red read in diameter to form or provide an upwardly facing annular shoulder or seat 33. A

ball valve 34 is provided in the opening 32 to cooperate with the seat 33. The valve 34 is adapted to seal downwardly against the seat to prevent the downwardly flowing circulation fluid from entering the inner barrel l2 and is adapted to move off its seat 33 when thecore entering the inner barrel displaces fiuid outwardly through the opening 32. Lateral ports 35 may be provided in the wall of the head member 3! to place the opening 32 in communication with the fluid passage P. g

In accordance with the invention an internal flange 33 is,provided on the head member 3| inwardly inclined guide surface 33. Theparts are preferably proportioned so that the upper portion of the head member 3| projects'into the opening llinthe sub l4 when the shell 21 rests on the shoulder 43. The upper outer corner 3! of the head member. 3| is preferably v bevelled ofl'.

The latch means i3 is provided to releasably hold the inner barrel l2 in its core receiving position in the outer barrel II. The means l3 serves to limit relative longitudinal; movement between the; barrels l0 and I2 when the drill is operating to cut or obtain a core. In accordance with the invention the latch means I3 is carried by the outer barrel II to cooperate with the inner barrel l2. In practice the latch means l3 may be carried or housed in the top sub I4 of the outer barrel Ill. The means l3 includes an upwardly facing abutment in the outer barrel assembly. This abutment may be in the nature of a ring 4| threaded in the opening l3 of the top sub l4 to be in spaced relation to the upper end of the sub l3 and to be spaced below the shoulder II. The means i3 further includes a shiftable ring 42 and latch dogs 43 carried by the ring 42 to cooperate with the head member 3| of the inner barrel l2. Thering 42 is shiftable vertically or longitudinally in the opening 13 above the abutment ring 4| and the ring It serves to limit its downward movement. An annular recess or groove 44 is preferably provided in the upper end of the latch-ring 42. The internal diameter of the ring 42 may be substantially the same as that of the abutment ring 4| and may be substantially the same as the diameter of the opening it above the shoulder ll. A plurality of circumferentially spaced longitudinal slots 45 is provided in the wall of the ring 42. Pins 43 are welded or otherwise fixed to thering 42 to pass transversely through the slots 4!. The pins 46 pivotally support the latch dogs 43. V

The-dogs 43 of the latch means l3 normally extend downwardly and inwardly from the slots 43, relative to the longitudinal axis of the tool, to project into the opening or the interior of the ring 42. Stop faces 49 are provided on the dogs 43 to cooperate with the wall of the opening it to limit the inward pivoting of the dogs. Notches 41 are provided in the upper or pivoted portions of the dogs 43 and torsional springs 43 are wrapped about the .pins 46 in the notches 41 to yieldingly hold the dogs 48 in their active positions where they project downwardly and inwardly in the interior of the ring 42. The

springs 43 have their ends reacting against the wallof the opening I and the walls of the notches 41 to yieldingly hold the dogs 43 in positions where their inner sides slope downwardly and inwardly relative to the vertical axis of the tool and where their lower ends are substantially horizontal. When the dogs 43 are in the position just mentioned their stop faces 4! engage the wall of the opening IS. The parts are related and-proportioned so that the upper end of the head members 3! is slightly below and in parallel 5 opposition to the lower ends of the dogs 43 when the shell 21 of the core catcher rests on the shoulder 4! to S pport the inner barrel l2.

In accordance with the invention spring means 7 is provided to yieidingly resist relative longitudinal movement between the latch ring 42 and the outer barrel II. A helical spring 50 is arranged under compression between the shoulder i1 and the upper end of thelatch ring 42. The lower end .of the spring I may be received in the groove 44 and the spring is arranged adjacent or against the wall of the opening l6 so that it does not interfere with the passage of the inner barrel I2 and other equipment through the opening. When the drill is in operation with the inner barrel I 2 in position within the outer barrel II the engagement of the core with the core catcher fingers 33 and with the barrel l2 may resist downward movement of the inner barrel with the outer barrel so that the ends of the fingers 43 cooperate with the upper end of the member 3| to urge the inner barrel l3 downwardly with the outer barrel ll. When very hard earth formation is encountered the lower resistance to downward movement of the inner 1 barrel l2 may suddenly increase. If this occurs the spring 50 holding thering 42 downwardly to resist relative movement between the barrels l0 and I2 yields or gives to remove shock from the inner barrel l2 and the spring 50 acting on the inner barrel l2 through the medium of the ring 42 and the dogs 43 may maintain a yielding downward pressure on the inner barrel |2 to cause it to feed downwardly with the outer barrel I0. When the resistance to downward movement of the inner barrel l2 becomes great the spring 50 may be fully compressed with its convolutions in contact so that the latch means I 3 comprising the dogs 43, the ring 42 and the spring 50, serves to definitely limit relative vertical movement between the barrels I0 and H and to positively urge the barrel l2 downwardly with the barrel H).

In accordance with the invention the inner barrel I2 is adaptedto be removed from theouter barrel l0 to recover or withdraw the core from the well. The latch means I3 is designed to be released by a spear type tool and the head member 3| of the inner barrel I2 is provided with the shoulder 31 to be engaged by the grappling parts of a spear. In the drawings I have ployed to lower the spear A into the drill stem S and to withdraw the spear from the string after it has obtained a holding engagement with the inner barrel l2. The shank 52 of the spear A is provided at its lower end with a reduced stem 53 providedwith a diametri'c slot 54. The lower endof the slot 54- is preferably closed by a plate 55. A ring 56 surrounds the upper portion of the slotted stem 53 and is welded or otherwise fixed to the stem and the shank 52. A pin 51 is arranged through openings 58 in the ring 56 and the stem 53 to pass transversely through the upper portion of the slot 54. Two

oppositely facing dogs 59 are pivoted on the pin 51 to operate in the slot 54. A helical spring 60 is arranged under compression between the opposing inner sides of the dogs 59 to yieldingly urge the dogs outwardly. The ends of the spring 6|! may be received in sockets 6| in the dogs 59. The ring 56 confines the upper portions of the dogs 59 to limit their outward pivoting, the lower ends of the dogs 59 are sharpened or pointed and the dogs are barbed or provided with upwardly facing shoulders 62. The shoulders 62 are provided on the outer sides of the dogs 59 and the spring 60 acts on the dogs to normally hold them where they project outwardly from the slot 54. The dogs 59 are adapted to retract into the slot 54.

In the operation of the core drill the outer barrel l0 carrying the cutting head may be operated on the lower end of the drilling string S in the usual manner. When it is desired to obtain a sample or core of the earth formation the inner barrel I2 is lowered or dropped through the string S into the outer barrel Ill. The inner barrel I2 is adapted to move downwardly through the subs l4 and I8 to come to the position where the lower end of the shell 21 engages the shoalder 40. During this entrance of the inner barrel Ill the inner barrel contacts the sloping inner sides of the dogs 43 and retracts the dogs so that the dogs do not interfere with the downward movement 01' the inner barrel. When the inner barrel l2 approaches its flnal position in the outer barrel II the upper end of the head member 3| moves past the dogs 43 and the dogs urged outwardly by the spring 48 automatically return to the positions illustrated in Fig. 2 o! the drawings where their lower ends oppose the upper end or the member 3|.

The drill is now in condition for operation to obtain a core. As the drill is rotated and fed downwardly in the usual manner circulation fluid is pumped downwardly through the drilling string S to flow through the opening It, the opening 32, the ports and the passage P to the discharge ports 25 in the head The valve 34 prevents the downwardly flowing fluid from entering the upper end of the inner barrel l2. During the core drilling operation the engagement of the core with the spring fingers 30 and with the interior of the inner barrel l2 may resist downward movement of the inner barrel and the lower ends of the dogs 43 may move downwardly against the upper end of the member 3| to urge the inner barrel downwardly with the outer barrel Ill. The spring 56 yieldingly urges the ring 42 downwardly with the outer barrel Ill and acts through the medium of the ring and the dogs 43 to yieldingly urge the inner barrel downwardly with the outer barrel. In the event that hard earth formations are encountered the spring 56 yields to relieve the inner barrel 2 of sudden shock.

When a core of sufficient length has been obtained the spear A is lowered through the drilling string S on a wire line or cable and passes downwardly through the opening l6. The stem 53 is adapted to enter the opening 32 and during' the passage of the stem 53 into the opening 32 the pointed ends of the dogs 59 engage the inclined surface 38. This engagement results in retraction of the dogs 59 so that the barbed ends of the dogs pass through the flange 36. When the shoulders 62 pass the flange 36 the dogs 59 spring outwardly so that their shoulders 62 are engageable with the shoulder 31. Substantially simultaneous with the passage of the dogs 59 through the flange 36 the lower end of the ring 56 comes into engagement with the inclined inner sides of the dogs 43 and retracts the dogs into the slots 45. The ring 56 is adapted to retract or move the dogs 43 to positions where the member 3| and the other parts of the inner barrel I2 may move upwardly past the dogs. Fig. 3 of the drawings illustrates the spear A in the position where its dogs 59 have their shoulders 62 in engagement with the shoulder 31 and its ring 56 is in engagement with the dogs 43 to hold them retracted. When the spear is in the position illustrated in Fig. 3 of the drawings it may be pulled upwardly on its wire line or cable to withdraw the inner barrel |2 from the drill. It will be apparent how the shoulders 62 of the dogs 59 cooperating with the shoulder 31 transmit upward movement to the inner barrel |2 so that the inner barrel moves upwardly with the spear A. The bevelled corner 39 of the member 3| moves into engagement with the dogs 43 to retract the dogs as the ring 56 moves upwardly out of engagement with the dogs, and the exteriors of the member 3|, the barrel section 26 and the shell 21 engage the dogs 43 to maintain them retracted during the removal of the inner barrel from the well. When the inner barrel I2 is drawn upwardLv as just described.the spring flngers 36 cooperate with the core to assist in breaking the core free from the earth formation and to trap and support the core so that it is retained in-the inner barrel l2 and recovered with the inner barrel. The inner barrel i2 carrying the core is readily pulled upwardly through the drilling string 8 by the wire line or cable carrying the spear A.

Having described only a typical preferred form and application of my invention, I do not wish to be limited or restricted to the specific details herein setv forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the art or fall within the scope of the following claims.

Having described my invention, I claim:

1. In a core drill, an outer barrel, a removable inner barrel in the outer barrel, shiitable latch means in the outer barrel cooperable with the inner barrel, and yielding means resisting upward movement of the latch means in the outer barrel.

2. A well core drill including a tubular outer .barrel to be connected with a rotary well drilling outer barrel, and a pivoted latch dog on the member engageable by the inner barrel.

3. A well core drill including a tubular outer barrel to be connected with a rotary well drilling string, cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outer barrel to receive the core, an upwardly facing surface on the inner barrel, a latch shiftably supported in the outer barrel and cooperable with the said surface, and spring means carried by the outer barrel resisting upward movement of the latch in the outer barrel and thereby urging the inner barrel to move downwardly with the outer barrel.

4. A well core drill including a-tubular outer barrel to be connected with a rotary well drilling string, cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outer barrel to receive the core, and means for releasably latching the inner barrel in the outer barrel, comprising a member shlftable in the outer barrel, spring means resisting movement of the member in the outer. barrel and a latch on the'member cooperable with the inner barrel.

5. A well core drill including a tubular outer barrel to be connected with a rotary well drilling string: cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outerbarrel to receive the core, and means for releasably latching the inner barrel in the outer barrel, comprising a member shiftable in the outer barrel, spring means resisting upward movement of the member relative to the outer barrel, and a retractable dog on the member engageable by the inner barrel.

6. A well core drill including a tubular outer barrel to be connected with a rotary well drilling string, cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outer barrel to receive the core, and means for releasably latching the inner barrel in the outer barrel, comprising a member shiftable in the outer barrel, spring means resisting upward movement of the member relative to the outer barrel, and a spring urged latch dog on the member retractable by the inner barrel when the same is moved into the outer barrel, the dog having a face engageable by the upper end of the inner barrel when the same is in position in the outer barrel to latch the inner barrel in the outer barrel.

7. A well core drill including a tubular outer barrel to be connected with a rotary well drilling string, cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outer barrel to receive the core, and releasable means in the outer barrel adapted'to yieldingly latch the inner barrel against movement relative to the outer barrel, said means including a ring shiftable in the outer barrel, 9.- spring in the outer barrel resisting upward movement of the ring therein, and retractable spring urged latch dogs on the ring for cooperating with the inner barrel.

8. A well core drill including a tubular outer barrel to be connected with a rotary .well drilling string, cutting means on the outer barrel for forming a core, an inner barrel movable through the drilling string and adapted to seat in the outer barrel to receive the core, releasable means in the outer barrel for latching the inner barrel therein comprising a shiftable spring held member carried by the outer barrel and pivoted latch dogs on the member engageable by the inner barrel and having downwardly and inwardly in clined upper surfaces when in latching engagement with the inner barrel, an internal shoulder on the inner barrel, and a tool operable in the drilling string to engage said surfaces to release the latch dogs and engageablewith the shoulder to withdraw the inner barrel from the string.

JESSE C. SMETHERMAN. 

